Let's divide 587582 by 21
The aim is to understand the frequency of 21 in 587582.

Moving on to step 1:
If we divide 5 by 21, we get 0 and a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 5 to get 5.
Bring next digit (8) of the dividend behind the 5 and repeat the process: 58 / 21

Going ahead to step 2:
When dividing 58 by 21, we get 2 with a remainder of 16.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
Subtract 42 from 58 to get 16.
Take the next digit (7) from the dividend and append it to 16, then repeat: 167 / 21

Moving on to step 3:
If we divide 167 by 21, we get 7 and a remainder of 20.
The number 7 becomes the next digit in our result. 
Result so far: 27.0
Deduct 147 from 167 and we're left with 20.
Include the next digit (5) from the dividend after 20, then repeat: 205 / 21

Going ahead to step 4:
When dividing 205 by 21, we get 9 with a remainder of 16.
The next digit of our result is 9. 
Result so far: 279.0
If we take 189 away from 205, we end up with 16.
Append the next digit (8) from the dividend to 16 and continue with: 168 / 21

Moving on to step 5:
The number 21 fits into 168 8 times, leaving a remainder of 0.
The next digit of our result is 8. 
Result so far: 2798.0
Subtract 168 from 168 to get 0.
Take the next digit (2) from the dividend and append it to 0, then repeat: 2 / 21

Let's proceed to step 6:
When dividing 2 by 21, we get 0 with a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 27980.0
Deduct 0 from 2 and we're left with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Advancing to step 7:
If we divide 20 by 21, we get 0 and a remainder of 20.
Record the quotient 0 as the next digit in the result. 
Result so far: 27980.0
If we subtract 0 from 20, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Advancing to step 8:
If we divide 200 by 21, we get 9 and a remainder of 11.
The number 9 becomes the next digit in our result. 
Result so far: 27980.09
Subtract 189 from 200 to get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Step 9:
The number 21 fits into 110 5 times, leaving a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 27980.095
If we subtract 105 from 110, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Going ahead to step 10:
21 can be fit into 50 2 times, resulting in a remainder of 8.
The number 2 becomes the next digit in our result. 
Result so far: 27980.0952
The remainder is 8 after subtracting 42 from 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Moving on to step 11:
21 goes into 80 3 times with a remainder of 17.
Write down 3 as next digit of the result. 
Result so far: 27980.09523
The remainder is 17 after subtracting 63 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Moving on to step 12:
The number 21 fits into 170 8 times, leaving a remainder of 2.
Use 8 as the next digit of our solution. 
Result so far: 27980.095238
Subtracting 168 from 170 leaves us with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Step 13:
21 goes into 20 0 times with a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 27980.095238
Subtract 0 from 20 to get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Moving on to step 14:
If we divide 200 by 21, we get 9 and a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 27980.09523809
If we subtract 189 from 200, we get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

The final outcome is 27980.09523809, with a leftover of 1.1e-08.